Firing mechanism



y 1945- c. v, CROCKETT, JR ET AL 2,375,627 v v FIRING MECHANISM FiledMarch 8, 1943 5 Sheets-Sheet l Snnmtors attorneys May 8, 19455.

c. v. CROCKETT, JR, ET AL FIRING MECHANISM 3 She etsL-Sheet 2 FiledMarch s, 1945 y c. v. CROCKETT, JR, ET AL 2,375,627

FIRING MECHAN ISM Filed March 8, 1943 3 Sheets-Sheet 5 W mm a 7Inventors Patented May 8, 1945 UNITED STATES. PATENT OFFICE. Y

FIRAIN G MECHANISM Clarence V; Crockett, Jr., Birmingham, and

Ghristiaan H. Bouvy, Detroit, Mich, assignorsto GeneralMotors-Corporation, Detroit, Mich a corporation of Delaware- ApplicationMarch'S, 1943, Serial No. 4781372 7 Claims. ('01. 89-28) This inventionrelates to gun firing mechanism. Its development arises from the desireto provide electrical firing for a howitzer which originally wasdesigned for lanyard firing. In such gun the usual firing mechanism isof the double action type in which pull of the trigger on thegun firstretracts and then releases the firing pin. A variable effort of fromabout twenty pounds up to a maximum of about sixty-five pounds isrequired through a travel of about two and one-half inches, The amountof power required to operate the trigger on the howiter is greater thancan be developed by any reasonable size electrical solenoid yetelectrical firing is desired in conformity with usual tank and guncarriage practice.

An object of the invention is to provide firing mechanism under controlof a relatively small solenoid, which can be easily and quickly appliedto existing howitzer structure and adopted for I immediate use in guncarriage and tank installations.

A further object of the invention is to provide for trigger actuation bythe electrical energization of a solenoid which merely operates a latchand releases a powerful force previously stored as an incident to gunrecoil action.

Another object is to take advantage of the howitzer travel in return toits in battery position to put energy into a spring, this energy laterbeing utilized to pull the trigger in the howitzer breech. Anotherobject is to provide for automatic restoration of the latching mechanismafter the gun has been fired and before howitzer return motion againstores energy in the trigger actuating spring.

Other objects and advantages will become apparent in the course of thefollowing specification having reference to the accompanying drawingswherein Figure 1 is a top plan view of a portion of a howitzer to whichthe invention has been applied; Figure 2 is a side elevation looking inthe direction of the arrows on line 22 of Figure 1 showing the triggeractuating parts in cocked position; Figure 3 is a fragmentary view ofthe parts shown in Figure 2 at the limit of released position; Figure 4is a detail sectional view on a large scale taken on line 4-4 of Figure1 and Figure 5 is an enlarged sectional view on line 55 of Figure 2.

With the exception of Figure 3 all the views in the drawings illustratethe parts in battery position and locked against firing by means of thehand lever mechanism best shown in Figure 4. This hand lockout will bedisregarded in the initial description of the structure and operation.

In the conventional howitzer installation a pair of recoil cylinders llcontain springs, not shown, which act against plungers carried by thebreech 2 for the gun barrel 3 and cushion recoil of the gun and urge ittoward the left in g ral for holding the gun in battery position. Astationary boss or plate 4 adapted to be secured on a suitable guncarriage and forming part of a fixed cradle mounts the forwardextremities .of a pair of upper and lower frames 5' and 6, respectively,each of which consists of a tube formed to generally U-shape outline andprojected rearwardly above and below the breech. Welded to the rear ofthe upper frame 5 is a mounting plate I having bolted on the underside aU-shaped strap 8 to the dependent spaced legs of which are fastened theends of a forwardly projecting U-shaped bracket 9.

Also mounted inthe dependent legs of the support bracket 8 for rotationis a rockshaft Ill which at its right end has pinned or fixed thereon alever arm I I connected by a flexible cable or chain I2 with the triggerarm I3 in a movable breech block, Engaged with the trigger actuatinglever H is one leg of a torsional coil spring Hi whose opposite endbears against the support bracket 8. The winding of the spring and itsaction on the rockshaft is such as to. impart a rotating tendency to therockshaft ill in a clockwise direction as viewed in Figure 2, whereby inthe absence of a stronger opposing force the rockshaft will be turneduntil a lever arm I5 pinned at the opposite or left end of the shaft 10comes into engagement with one. side of a stop pin indicated at [6. Thestop pin l6 also serves as an abutment for the lever l5 to limit itsrotation in counterclockwise direction as indicated in Figure 3 of thedrawings, when counterclockwise movement occurs to exert pull on thechain {2 for firing the gun. Trigger actuating movement is supplied byforce storedin a heavier coil spring H which force in the cockedpositionof the parts, predominates thatof the return spring l4. s

A link I8 joins one end of the main spring H to a lever arm 19 pinned orkeyed to the rockshaft Ill. The other end of the springll engages across bar 20 of a yoke having forwardly projecting pins 2-l2| slidablymounted in the stationary boss 4. Adjustable nuts 22 carried by the pins21 are engageable with the front face of the boss 4- 1 for limitingrearward. movement of the yoke upon stationary boss 4. This relieves allor nearly all the tension in the spring I! so that the force of therestoring spring M. then takes precedence for returning the rockshaft IDto original position Nowif the rockshaft after return is retained bysuitable latch mechanism, the return motion of the gun barrel throughthe recoil cushioning mechanism brings the abutment ears 23 intoengagement with and picks up the spring anchoring yoke to carry itforward and stretch or extend the main spring I! for again storingenergy therein for a subsequent firing operation.

To keep the spring I! under tension the rockshaft retainer arm I isarranged to engage at its free end with the end of a latch lever 24pivotally mounted on the fulcrum pin 25 fixed in the mounting bracket 9on an axis in spaced parallelism with the axis of the rockshaft. Acoiled torsion spring 26 yieldably depresses the latch lever 24 into thepath of the rockshaft arm I5 to the limit provided by a stop pin 2!projecting laterally from the bracket 9 into a V-shaped notch at theopposite end of the latch lever 24. This same stop pin 21 extends into asimilar notch in a release lever 28 and limits movement thereof.

The release lever 28 is arranged beside the latch 24 and is coaxialtherewith on the fulcrum pin 25. A shoulder or ratchet stop formed onthe release lever 28 is provided to engage one arm of a pawl or bellcrank 29 pivoted on the free end of the latch 24 and provided with atorsion spring 54 which tends to rock the bell crank for releasablymaintaining engagement with the stop on the lever 28. Its opposite armprojects downwardly so as to be in the path of return movement, of therockshaft arm l5 to break the connection between the levers 24 and 28.Thus normally the bell crank 29 servesas a strut to transmit motion fromthe lever 28 to the latch 24 when the lever is moved in acounterclockwise direction as viewed in Figure 2 for freeing therockshaft. Then upon return of the rockshaft under its restoring springl4 and irrespective of the position of the release lever 28 the bellcrank or pawl 29 upon being struck by the arm I5 immediately allows thelatch 24 to drop into locking engagement with the arm l5 under influenceof the spring 26. For restoring the parts after force is solenoid 3!mounted on the frame bracket 9 and having a projectible plunger 32 toengage the lower arm of the release lever 28. Plunger projection uponenergization of the solenoid will serve to retract the latch butthereafter as soon as the rockshaft is returned and regardless ofcontinued plunger projection, the latch will return to position forholdin the firing mechanism cocked. Even though the gunners finger isnot removed from the solenoid switch button before start of howitzerrecovery from recoil, latching of the rockshaft occurs. Thus relatchingis independent of solenoid plunger position. As soon as the gunner doesrelease the firing switch button the solenoid circuit is broken toenable plunger retraction and the lever 23 reassumes its originalposition under tension of the spring 30. Then the bell crank or pawl 29is forced by its torsional spring into its original position and the gunis again ready to fire.

In case of failure of electr c power or other cause which makes thefiring solenoid inoperative,

'hand firing also has been provided. For hand firing purposes theopposite arm of the lever 28 is provided with an elongated slot slidablyreceiving the pin in a clevis 33, which in the cocked position of theparts is at the front or bottom of the slot in condition to release thelatch upon the pull on the rod 34 fixed to the clevis 33. As shown inFigures 1 and 2 the forward end of the pull rod 34 is connected by aclevis 35 to a lever arm 36 on a rockshaft 31 mounted in the stationaryboss 4 and provided with a hand crank 38. Rearward pull on the handle 38will rotate lever 28 in the same direction as it is rotated by thesolenoid and actuate the firing mechanism.

Provision is also made for manual cooking of the parts as may becomenecessary in the case of misfiring or for initially setting up the partsfor the first shot. Accordingly a hand crank 39 is mounted on thefulcrum pin 25 and is connected by a link 48 to a lever arm 42 pinned onthe rockshaft ID. This lever arm 42 is in the form of a sector having anarcuate slot to which is fitted a pin 43 on the end of the link 40. Thehand crank 39 may be moved between the forward limit shown by full linesand the rearward limit shown by dotted lines in Figure 4. In eitherlimit it abuts the supporting parts of the firing mechanism and isreleasably retained in either position by being connected to anovercenter coil spring 44, whose point of attachment on the levercarried lateral pin 4| moves above or below center as the case may beand in either position exerts sufficient pull to prevent accidentaldisplacement of the crank.

When the gun is to be fired the hand crank 39 is swung to its rearwardor broken line position, wherein the link pin 43 is moved forward in theslot of the sector arm 42. Upon rocking of the shaft NJ to fire the gunthe sector arm will be carried forward until the rear end of its slotapproaches the broken line position of the pin 43 in Figure 4. Shouldautomatic return of the rockshaft to latched position fail then forwardswinging of the hand crank 39 by reason of the engagement of the pin 43with the rear end of the slot in the sector 42 will return the parts tococked position. As long as the hand lever is leftin forward full lineposition, engagement of the pin 43 with the sector will prevent refiringof the gun. It will be noted in Figure 4 that the joint between thelever 39 and the link 40 is above a line which would intersect the pins43 and 25 and the overcenter relation tends to maintain the partsagainst breakage of the joint under influence of any force tending torotate the rockshaft in counterclockwise direction. Thus the handcocking lever 39 serves the'additional purpose of a safety device tosupplement the latch and to prevent rotation of the rockshaft underinfluence of the main spring I I in the event the latch becomesinoperative or is released accidentally at a time When firing is notdesired.

We claim:

1. A gun having a fixed cradle, a barrel mounted on the cradle forrecoil movement and firing mechanism including a rockshaft mounted onthe cradle for movement between firing and cocked position, a triggercarried with the barrel and operatively connected with the rockshaft, aretainer arm fixed on the rockshaft, a retractible latch member arrangedto project into the path of and to block the retainer arm in its cockedposition to lock the rockshaft against rotation in gun firing direction,a latch release member positioned adjacent the latch member, a pawlcarried by one of the members and releasably engaged with the othermember to transmit latch releasing movement therebetween, means on saidpawl arranged to be struck by the shaft retainer arm on its return tococked position and thereby release pawl engagement with said othermember, a relatively light spring operatively connected with therockshaft for urging return of the retainer arm to latch engaging cockedposition, a relatively heavy spring operatively connected at one endwith the rockshaft for urging the rockshaft to firing position uponlatch release and means operatively connecting the opposite end of thelast mentioned spring with the barrel so that the spring force decreasesbelow that of the first mentioned .spring upon barrel recoil travel.

2. A gun having a fixed cradle, a barrel mounted on the cradle forrecoil movement and firing mechanism therefor including a triggercarried with the barrel, a trigger actuating rockshaft carried by thecradle, a spring operatively connected with the shaft to impart rockingmotion to cocked position, a second spring operatively connected withthe shaft to rock the same away from cocked position, means operativelyconnecting the last mentioned spring with the barrel and operative withrecoil to decrease the force of the last mentioned spring and enable thefirst spring to rock the shaft, a latch engageable part on therockshaft, a spring pressed latch mounted on the cradle and engageablewith said part on the rockshaft to lock the rockshaft in cockedposition, a release member coacting with said latch and mounted formovement relative thereto, a pawl carried by the latch and engageablewith the release member to transmit member movement in one direction tothe latch for releasing the rockshaft, said pawl also being engageablewith the rockshaft part in its return to cocked position for trippingthe pawl from engagement with the release member and insuring latchengagement with the rockshaft part regardless of restoration of saidrelease member.

3. In a gun having a fixed cradle and a barrel mounted on the cradle forrecoil action, trigger actuating mechanism including a rockshaft havinga lever arm and being mounted on the cradle, a pair of spring elementsoperatively connected with the rockshaft to exert opposing forces on therockshaft, means anchoring one of said springs on the gun barrel so thatits exerted force is variable and is predominant in gun battery positionbut is inefiective against the exerted force of the other spring uponrecoil action of the gun barrel, a latch positioned adjacent anddetachably engageable with said rockshaft arm to retain the samereleasably cocked, an electrical solenoid having a plunger, a pawldevice interposed between the plunger and the latch to transmit plungertravel to the latch for releasing the rockshaft for its actuation underpredominant spring forces, first in trigger actuating direction andthen, as a result of gun barrel recoil, in the opposite direction, saidpawl being arranged to be struck by the arm of the rockshaft in itsreturn travel and thereby be shifted out of plunger and pawl motiontransmitting relation for enabling latch reengagement with saidrockshaft arm irrespective of solenoid plunger position.

4. In a gun having a fixed cradle and a barrel mounted on the cradle forrecoil travel, firing.

mechanism including a rockshaft mounted on the cradle and rotatable fromcocked position to fire the gun, an actuating spring operativelyconnected at one end with the rockshaft for exerting force to rock saidshaft away from cocked position, mean mounting the opposite end-of saidspring for movement with gun barrel travel whereby spring force isdecreased upon recoil travel, a second spring operatively connected withthe rockshaft to return the same to cocked position and a releasablelatch to hold the rockshaft on its return to cocked position.

5. In a gun having a fixed cradle and a barre mounted on the cradle forrecoil travel, firing mechanism including a rockshaft mounted on thecradle and rotatable from cocked position to fire the gun, an actuatingspring operatively connected with the rockshaft for exerting force torock said shaft away from cocked position, a spring anchoring membercarried by the barrel so that spring force decreases upon gun recoiltravel, .a second spring operatively connected with the rockshaft toreturn the same to cocked position, a rockshaft latch, a solenoid havinga plunger member operable to move the latch to release position uponsolenoid energization, a motion transmitting trip pawl interposedbetween the latch and said member and means to trip said pawl out ofmotion transmitting relation to the member and the latch upon return ofthe rockshaft.

6. In a gun having a fixed cradle and a barrel mounted on the cradle forrecoil movement, firing mechanism, including a trigger actuatingrockshaft mounted on the cradle, a pair of springs operatively connectedwith the rockshaft in opposing thrust relation, means joining one ofsaid springs to the barrel for travel with barrel recoil to render itsforce ineffective against the other spring, a pair of lever armsseparately pivotally mounted side by side on a common axis radiallyspaced from the axis of the rockshaft, a lever carried by the rockshaftand releasably retaining the rockshaft cooked by engagement with the endof one of said pair of lever arms, spring means active on the lastmentioned lever arm and yieldably retaining it in latched engagementwith the rockshaft lever, a bell crank pivoted on the end of the-lastmentioned lever arm, a spring active on the bell crank to urge one crankarm into engagement with a thrust seat on the other lever arm and toproject its other crank arm into the return path of the rockshaft leverso as to be struck to free the bell crank from the last mentioned leverarm, a solenoid having a .projectable plunger to strike and swing thelast mentioned lever arm upon energization of the solenoid and a springexerting its force on said lever arms to spread their free ends apart.

'7. Gun firing mechanism including a trigger actuating rockshaftoscillatable from cocked position to firing position and back to cockedposition, a lever arm fixed on the rockshaft for swinging to and frotherewith, a spring pressed latch engageable with said arm in its cockedposition, a release member pivoted in side by side' coaxial relationwith said latch, a trip pawl interposed between the latch and itsrelease member to provide a motion transmitting connection, a part onthe pawl projecting into the return path of the rockshaft lever arm tobe struck to break said connection, and a solenoid having a plungerengageable with the release member to actuate the same upon electricalenergization of the solenoid.

CLARENCE V. CROCKETT, JR.

CHRISTIAAN H. BOU V Y

